Question

表类

public Table() {
    height = 0.0;
    weight = 0.0;
    color = "unknown";
    numberOfLegs = 4;
    inventoryNumber = 1;
    numberOfTables++;
}// no args contructor

public Table(double h, double w, String c, int n) {
    height = h;
    weight = w;
    color = c;
    numberOfLegs = n;
    inventoryNumber = 2;
    numberOfTables++;
}// constructor

亚军课

Table kitchenTable = new Table();
Table diningTable = new Table(5.5, 9.9, "brown", 8);
Table picnicTable = new Table(3.3, 4.4, "red", 6);
Table babyTable = new Table();

如何在不使其成为静态变量的情况下增加库存编号例如，我的跑步者类具有2个没有args构造函数和System out println两者，但是它们都具有1。而我想要第一个打印出1和第二个打印出2

Answer 1

您有两个选择

可变

将此方法添加到您的Table类中

public void incrementInventory() {
     this.inventoryNumber++;
}

用法

Table mutableTable = new Table();
mutableTable.incrementInventory();

不变（推荐）

将此添加到您的Table类

// new constructor
public Table(double h, double w, String c, int n, int inventory, int tables) {
    height = h;
    weight = w;
    color = c;
    numberOfLegs = n;
    inventoryNumber = inventory;
    numberOfTables = tables;
}

public Table incrementInventory() {
     // new Table with the same all variables and inventory + 1
     return new Table(
         this.height, this.weight , this.color , this.numberOfLegs ,
         this.inventoryNumber + 1, this.numberOfTables 
     );
}

用法

Table inmutableStateOne = new Table();
Table inventoryPlusOne = inmutableStateOne.incrementInventory();

然后，inmutableStateOne将保持您的初始状态，而inventoryPlusOne不变，但使用inventory + 1

在面向对象的程序中增加一个私有实例变量

1 个答案: